Recently, there are demands for reducing energy consumption in factories and offices (buildings) and at home. According to statistical data on energy consumption, the ratio of energy consumption by all households to total energy consumption is relatively high, and reduction in energy consumption at home has been an issue. A technique to manage energy consumption at home is called an HEMS (Home Energy Management System). The conventional HEMS is for providing energy saving measures such as on-off control of electrical appliances such as air conditioner and collection of logs of power consumption and the like.
Meanwhile, power generation utilizing renewable energy in place of fossil fuels is becoming into practical use and this trend looks set to be stronger in the future. Examples of power generation utilizing renewable energy that is being developed include photovoltaic power generation, wind power generation, biomass power generation, and wind power generation. Indeed, installation of solar panels on roofs, walls and the like for photovoltaic power generation at home is being widely spread.
A solar panel is usually connected with a power conditioner including a DC-DC converter and a DC-AC inverter as disclosed in Patent Document 1.